<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        let num = +prompt("请输入一个数字")
        switch (num){
            case 1:
                alert("星期一")
                break
            case 2:
                alert("星期二")
                break
            case 3:
                alert("星期三")
                break
            case 4:
                alert("星期四")
                break
            case 5:
                alert("星期五")
                break
            case 6:
                alert("星期六")
        }
    </script>
</body>
</html>